A Randomized Crossover Trial Comparing Glucose Control between Different Exercise Types in Adolescents with Type 1 Diabetes Using a Hybrid Closed-Loop System

Background: Hybrid closed loop (HCL) systems may mitigate the glycemic impact of different exercise types in youth with type 1 Diabetes. Aims: Glucose was compared during and following moderate intensity exercise (MIE), high intensity interval exercise (HIE) and resistance exercise (RE) in adolescents using HCL insulin delivery. Methods: Adolescents using HCL (Medtronic Minimed 670G) undertook 40 min of MIE, HIE and RE in random order. A temporary glucose target was set 2 hours prior and during exercise with 15g carbohydrate given pre-exercise if glucose level was <126mg/dL. A standardized dinner was eaten 4 hours after exercise. The primary outcome was sensor glucose percentage time in range 70-180mg/dL (TIR) for 12 hours from exercise onset. Results: Twenty-eight participants (50% female); age [mean (SD)] 16.3(2.1) years; diabetes duration 9.4(4) years; HbA1c 7.3(0.6)% [56(7)mmol/mol], completed the study. In the 12 hrs following exercise onset the TIR for MIE was [median (IQR)] 76(60-92)%, HIE 87(78-96)% and RE 85(69-94)% (MIE v HIE; (p=0.015). Time >180mg/dL (TAR) was greater for MIE v HIE (18[3-25]% v 7[0-15]%; p=0.041). Time <70mg/dL (TBR) did not differ between MIE, HIE and RE [0 (0-7)%; 2(0-9)%; and 2(0-10)% respectively]. After the post-exercise meal (280-715mins), TIR for MIE was lower than HIE [86(76-96) v 67(49-87)%; p=0.003] and TAR was higher for MIE than HIE [5(0-19) v 28(0-41)%; p=0.012]. There was no significant difference between exercise types in TIR, TAR and TBR during exercise (0-40min) and before dinner (40-280mins). There was a total of 8 episodes of hypoglycemia (15mins <54mg/dL) each for MIE and RE and 5 for HIE. Conclusion: Glucose control in the post meal period following exercise differed between HIE and MIE but not RE. Hypoglycemia occurred across all exercise types. Disclosure R. Seckold: None. D. Morrison: None. J. Rafferty: None. S. R. Valkenborghs: None. B. Paldus: None. D. P. Zaharieva: Speaker's Bureau; American Diabetes Association. Research Support; Hemsley Charitable Trust, International Society for Pediatric and Adolescent Diabetes, Insulet Corporation. Advisory Panel; Dexcom, Inc. Speaker's Bureau; Ascensia Diabetes Care, Medtronic. M. C. Riddell: Stock/Shareholder; Supersapiens. Advisory Panel; Zealand Pharma A/S. Speaker's Bureau; Dexcom, Inc. Consultant; Lilly Diabetes. Speaker's Bureau; Novo Nordisk, Sanofi. Stock/Shareholder; Zucara Therapeutics. Advisory Panel; Zucara Therapeutics, Indigo Diabetes. Consultant; Eli Lilly and Company, Jaeb Center for Health Research. C. E. Smart: None. D. N. O'Neal: None. B. R. King: None. Funding JDRF (3-SRA-2018-532-M-B)